Update on the role of topotecan in the treatment of recurrent ovarian cancer

Acid-Promoted Cyclization of α-Azidobenzyl Ketones through C═N Bond Formation: Synthesis of 6-Substituted Quinoline Derivatives

An acid-promoted cyclization of α-azidobenzyl ketones has been developed for the synthesis of 6-substituted quinoline derivatives. A variety of synthetically useful 6-OTf or -OMs quinoline derivatives were obtained in moderate to good yields. The reaction proceeds via C═N bond formation without organophosphine, providing convenient access to structurally interesting and synthetically important 6-substituted quinoline derivatives in moderate to good yields. A mechanistic perspective that is different from the traditional intramolecular Schmidt reaction has been proposed.

Targeting Microtubule-Associated Protein Tau in Chemotherapy-Resistant Models of High-Grade Serous Ovarian Carcinoma

Relapsed, recurrent, chemotherapy-resistant high-grade serous ovarian carcinoma is the deadliest stage of this disease. Expression of microtubule-associated protein tau (tau) has been linked to resistance to paclitaxel treatment. Here, I used models of platinum-resistant and created models of platinum/paclitaxel-resistant high-grade serous ovarian carcinoma to examine the impact of reducing tau expression on cell survival and tumor burden in cell culture and xenograft and syngeneic models of the disease. Tau was overexpressed in platinum/paclitaxel-resistant models; expression of phosphoSer396 and phosphoThr181 species was also found. A treatment with leucomethylene blue reduced the levels of tau in treated cells, was cytotoxic in cell cultures, and efficiently reduced the tumor burden in xenograft models. Furthermore, a combination of leucomethylene blue and paclitaxel synergized in eliminating cancer cells in cell culture and xenograft models. These findings underscore the feasibility of targeting tau as a treatment option in terminal-stage high-grade serous ovarian cancer.

Fabrication and characterization of sterically stabilized liposomes of topotecan

Background

Recently, the development of drug delivery which delivers controlled drug release at the tumor sites emerged as an attractive option for enhancing anticancer therapeutics. Next-generation nanotherapeutics must not contain only the nanoscale but should find their way to the solid tumor via active or passive targeting. Surface modification by pegylated lipids is one of the approaches used to made liposomes long-circulating and passively target the tumor. Pegylation of liposomes help them to alter the pharmacokinetics of drug molecule in vivo. The successful journey of such a complex drug delivery system from bench to clinic requires in-depth understanding and characterization. In this research, we fabricated and characterized sterically stabilized liposomes of topotecan which meets the clinical need. Liposomes have been prepared using ethanol injection-solvent evaporation method followed by extrusion for size reduction. Outer medium was replaced with an isotonic sucrose solution using dialysis followed by drug loading. We characterized liposomes’ membrane phase and dynamics, drug and lipid quantification, size distribution, state of encapsulated drug, internal volume and internal pH of liposomes, presence, and thickness of grafted PEG on the liposomes surface, and in vitro leakage test.

Results

All these studied parameters directly or indirectly provide information regarding the pharmacokinetic behavior of the formulation and the tumor-targeting property of the drugs in vivo. We encapsulated the topotecan in nanoliposomes with pegylation on the surface resulting in long-circulating stealth liposomes. Nanoliposomes remotely loaded with topotecan by transmembrane gradient method.

Conclusion

Our in vitro characterization of topotecan liposomes provides an explanation for the good therapeutic efficacy of tumor cells.

Elucidation of Mechanisms of Topotecan-Induced Cell Death in Human Breast MCF-7 Cancer Cells by Gene Expression Analysis

Topotecan is a clinically active anticancer agent for the management of various human tumors. While the principal mechanism of tumor cell killing by topotecan is due to its interactions with topoisomerase I and formation of DNA double-strand breaks, recent studies suggest that mechanisms involving generation of reactive free radicals and induction of oxidative stress may play a significant role in topotecan-dependent tumor cell death. We have shown that topotecan generates a topotecan radical following one-electron oxidation by a peroxidase-hydrogen peroxide system which reacts with reduced glutathione and cysteine, forming the glutathiyl and cysteinyl radicals, respectively. While little is known how these events are involved in topotecan-induced tumor cell death, we have now examined the effects of topotecan short (1 h) and long (24 h) exposure on global gene expression patterns using gene expression microarray analysis in human breast MCF-7 cancer cells, a wild-type p53 containing cell line. We show here that topotecan treatment significantly down-regulated estrogen receptor alpha (ERα/ESR1) and antiapoptotic BCL2 genes in addition to many other p53-regulated genes. Furthermore, 8-oxoguanine DNA glycosylase (OGG1), ferredoxin reductase (FDXR), methionine sulfoxide reductase (MSR), glutathione peroxidases (GPx), and glutathione reductase (GSR) genes were also differentially expressed by topotecan treatment. The differential expression of these genes was observed in a wild-type p53-containing breast ZR-75-1 tumor cell line following topotecan treatment. The involvement of reactive oxygen free radical sensor genes, the oxidative DNA damage (OGG1) repair gene and induction of pro-apoptotic genes suggest that reactive free radical species play a role in topotecan-induced tumor cell death.

Genomic data integration by WON-PARAFAC identifies interpretable factors for predicting drug-sensitivity in vivo

Integrative analyses that summarize and link molecular data to treatment sensitivity are crucial to capture the biological complexity which is essential to further precision medicine. We introduce Weighted Orthogonal Nonnegative parallel factor analysis (WON-PARAFAC), a data integration method that identifies sparse and interpretable factors. WON-PARAFAC summarizes the GDSC1000 cell line compendium in 130 factors. We interpret the factors based on their association with recurrent molecular alterations, pathway enrichment, cancer type, and drug-response. Crucially, the cell line derived factors capture the majority of the relevant biological variation in Patient-Derived Xenograft (PDX) models, strongly suggesting our factors capture invariant and generalizable aspects of cancer biology. Furthermore, drug response in cell lines is better and more consistently translated to PDXs using factor-based predictors as compared to raw feature-based predictors. WON-PARAFAC efficiently summarizes and integrates multiway high-dimensional genomic data and enhances translatability of drug response prediction from cell lines to patient-derived xenografts.

Gene Expression Indicates Altered Immune Modulation and Signaling Pathway Activation in Ovarian Cancer Patients Resistant to Topotecan

Epithelial ovarian cancer (EOC) is one of the deadliest gynecological malignancies. Topotecan remains an essential tool in second-line therapy; even so, most patients develop resistance within a short period of time. We aimed to identify biomarkers of topotecan resistance by using gene expression signatures derived from patient specimens at surgery and available subsequent responses to therapy. Gene expression was collected for 1436 patients and 10,103 genes. Based on disease progression, patients were categorized as responders/nonresponders depending on their progression free survival (PFS) state at 9, 12, 15 and 18 months after surgery. For each gene, the median expression was compared between responders and nonresponders for two treatment regimens (chemotherapy including/excluding topotecan) with Mann-Whitney U test at each of the four different PFS cutoffs. Statistical significance was accepted in the case of p < 0.05 with a fold change (FC) ≥ 1.44. Four genes (EPB41L2, HLA-DQB1, LTF and SFRP1) were consistently overexpressed across multiple PFS cutoff times in initial tumor samples of patients with disease progression following topotecan treatment. A common theme linked to topotecan resistance was altered immune modulation. Genes associated with disease progression after systemic chemotherapy emphasize the role of the initial organization of the tumor microenvironment in therapy resistance. Our results uncover biomarkers with potential utility for patient stratification.

Development of nanoscale approaches for ovarian cancer therapeutics and diagnostics

Ovarian cancer is the deadliest of all gynecological cancers and the fifth leading cause of death due to cancer in women. This is largely due to late-stage diagnosis, poor prognosis related to advanced-stage disease, and the high recurrence rate associated with development of chemoresistance. Survival statistics have not improved significantly over the last three decades, highlighting the fact that improved therapeutic strategies and early detection require substantial improvements. Here, we review and highlight nanotechnology-based approaches that seek to address this need. The success of Doxil, a PEGylated liposomal nanoencapsulation of doxorubicin, which was approved by the FDA for use on recurrent ovarian cancer, has paved the way for the current wave of nanoparticle formulations in drug discovery and clinical trials. We discuss and summarize new nanoformulations that are currently moving into clinical trials and highlight novel nanotherapeutic strategies that have shown promising results in preclinical in vivo studies. Further, the potential for nanomaterials in diagnostic imaging techniques and the ability to leverage nanotechnology for early detection of ovarian cancer are also discussed.

Camptothecin Enhances Cell Death Induced by (177)Lu-EDTMP in Osteosarcoma Cells

Lutetium-177 is an assured therapeutic radionuclide with favorable half-life and suitable β(-) energy. Radiolabeled (177)Lu-EDTMP (Ethylenediamine tetramethylene phosphonic acid) is by and large used for bone pain palliation in cancer patients. In vitro cell studies are carried out in osteosarcoma cells MG-63 to evaluate the combined effect of anticancer drug camptothecin (CPT) and (177)Lu-EDTMP. Two concentrations of (177)Lu-EDTMP (3.7 and 37 MBq) were incubated with MG63 cell line for 48 hours with and without pretreatment of CPT (10 nM) for 1 hour. After completion of incubation, the cells were harvested and cellular toxicity was estimated by LDH, MTT, and trypan blue dye. Apoptotic DNA fragmentation was estimated by ELISA kit. The expression of proteins such as bcl2, PARP, and MAPK (mitogen-activated protein kinase) that were related to apoptotic signaling pathways was assessed by western blotting. The results indicated that cellular toxicity and apoptosis were relatively higher in MG63 cells that were treated with CPT prior to treating with (177)Lu-EDTMP in comparison with the corresponding individual controls.

Escalating topotecan in combination with treosulfan has acceptable toxicity in advanced pediatric sarcomas

Patients with advanced pediatric sarcomas have a poor prognosis and novel combination therapies are needed to improve the response rates. Hematological and organ related toxicities have been observed when administering topotecan in combination with, e.g., high dose thiotepa. This study evaluates the toxicity of escalating doses of topotecan alone or in combination with thiotepa or treosulfan. We compared the toxicity including death of complication (DOC) of topotecan alone or in combination with thiotepa or treosulfan in advanced pediatric sarcomas (n = 12). Ten of 12 patients (0.83) suffered from advanced tumors of the Ewing family (i.e., bone or marrow metastases or relapse <24 month after diagnosis, including one neuroepithelial tumor of the kidney) and two from alveolar rhabdomyosarcoma stage IV (0.17). Median age was 15 years (range 5-28). Ratio of female to male was 1:1. Two patients received topotecan alone (1.25 mg/m(2) q 5d and 1.5 mg/m(2) q 5d), three patients received four courses of topotecan (2 mg/m(2) q d 1-5) in combination with thiotepa (100 mg/m(2) q d 1-5), and seven patients received topotecan (2 mg/m(2) q d 1-5) in combination with treosulfan (10g/m(2) q d 3-5). Overall toxicity was not different between all three groups; mean scores were 1.6, 1.8, and 1.7 according to WHO grading (Scale 0-4). Organ related toxicity ranged between 0 and 4 and was not different as well. DOC was 0/2, 1/3, and 0/7 patients respectively. Escalating therapy with topotecan in combination with treosulfan has acceptable toxicity and warrants further investigation in advanced pediatric sarcomas.

Phase 2 trial of docetaxel, gemcitabine, and oxaliplatin combination chemotherapy in platinum- and paclitaxel-pretreated epithelial ovarian cancer

BACKGROUND

This phase 2 trial was designed to evaluate the efficacy and toxicity of a combination of docetaxel, gemcitabine, and oxaliplatin for platinum- and paclitaxel-pretreated epithelial ovarian cancer.

PATIENTS AND METHODS

Heavily pretreated patients (N = 30; median age, 61 years) received docetaxel, 55 mg/m2; gemcitabine, 500 mg/m2 (day 1); and oxaliplatin, 70 mg/m2 (day 2) biweekly. Twelve patients had platinum-sensitive disease, and 18 patients had platinum-resistant disease.

RESULTS

Median follow-up was 18.6 months. No differences in patient characteristics were observed between patients with carboplatinum-sensitive and carboplatinum-resistant disease. In patients with carboplatin-sensitive disease, an overall response (OR) of 83.3%, a progression-free survival of 10.6 months, and an overall survival of 18.9 months were observed. In patients with carboplatinum-resistant disease, an OR was seen in 38.9% with a progression-free survival of 5.3 months and an overall survival of 16.3 months. Patients with platinum-refractory disease (progression under previous carboplatinum therapy, n = 13) had an OR of 23%, whereas patients with objective response but relapse less than 6 months after carboplatinum therapy had an OR of 80.0%. Grade 3 and 4 toxicities were only observed for anemia (6.7%), neutropenia (20.0%), thrombopenia, peripheral neuropathy, and diarrhea (16.7%). No neutropenic fever or treatment-related death occurred.

CONCLUSIONS

In comparison with current standard protocols, a combination of docetaxel, gemcitabine, and oxaliplatin showed considerably higher efficacy without remarkable increased toxicity; particularly for patients with early relapse after a platinum-containing therapy.

Review role of topotecan in gynaecological cancers: current indications and perspectives

BACKGROUND

Ovarian cancer is the fourth cause of death from gynaecological cancer and cervical cancer is the first in women <45 years old in developing countries. The aim of this article is to review the role of topotecan (Hycamtin), a semi-synthetic alkaloid derivative of camptothecin, in ovarian and cervical cancer in monotherapy and in combination.

METHODS

This article reviews the mechanism of action, pharmacokinetics, toxicity and efficacy of topotecan. The paper also reports the principal phases II and III studies of topotecan in advanced or recurrent ovarian and cervical cancer.

RESULTS

Topotecan (Hycamtin), currently indicated for the treatment of relapsed ovarian cancer, has demonstrated activity both in platinum-sensitive and in platinum-resistant disease. The combination cisplatin-topotecan for the treatment of advanced and recurrent cervical cancer has demonstrated a clinical benefit in terms of response rate, overall survival and progression free survival. Haematological toxicity of topotecan also is easy to manage and not cumulative, especially with the weekly scheduled recently introduced in clinical practice.

CONCLUSION

Topotecan (Hycamtin) will continue to play a role in the treatment of advanced ovarian and cervical cancer, in monotherapy or in combination with other cytotoxic agents.

NSC606985 induces apoptosis, exerts synergistic effects with cisplatin, and inhibits hypoxia-stabilized HIF-1alpha protein in human ovarian cancer cells

The camptothecins, which target the intranuclear enzyme topoisomerase I, have advanced to the forefront of several areas of developmental chemotherapy of cancers. In the present study, we investigated the potential anti-human ovarian cancer effects of NSC606985, a novel and rarely studied camptothecin analog, and its combination with cisplatin (CDDP). Human ovarian cancer cell line COC1 cells were treated with different nanomolar of NSC606985 with or without CDDP, and cell growth and apoptosis were evaluated, respectively, by MTT assay and annexin-V assay on flow cytometry. Chou-Talalay analysis was used to evaluate combined effect of NSC606985 and CDDP. Western blot was used to detect protein kinase Cdelta (PKCdelta), caspase-3 and hypoxia-inducible factor-1alpha (HIF-1alpha) proteins. Our results showed that NSC606985 at nanomolar concentration induced apoptosis with the activation of PKCdelta in COC1 cells. Especially, NSC606985 presented the significant combined effects on COC1 cells in terms of growth inhibition and apoptosis induction. In addition, NSC606985 significantly antagonized the accumulation of HIF-1alpha stabilized by hypoxia or hypoxia-mimetic agent. These results suggest that NSC606985 and its combination with CDDP present the therapeutic potential on ovarian cancer, and deserve further preclinical and clinical studies.

Molecular cytogenetic evaluation of the mechanism of micronuclei formation induced by camptothecin, topotecan, and irinotecan

We used the conventional bone marrow micronucleus test complemented with the fluorescent in situ hybridization with the minor satellite DNA probe to investigate the mechanisms of induction of micronuclei in mice treated with camptothecin and its clinical antineoplastic analogues topotecan and irinotecan. All experiments were performed with male Swiss albino mice. Single doses of 1 mg/kg camptothecin or 0.6 mg/kg topotecan were injected intraperitoneally and bone marrow was sampled at 30 hr (camptothecin) or 24 hr (topotecan) after treatment. A dose of 60 mg/kg irinotecan was injected intravenously, once every fourth day for 13 days and bone marrow was sampled 24 hr after the last treatment. In animals treated with camptothecin, a total of 1.07% micronuclei were found and 70% of them were centromere-negative, indicating their formation by DNA strand breaks and reflecting the predominant clastogenic activity of camptothecin. Exposure to topotecan and irinotecan yielded 1.71 and 0.83% micronuclei, respectively. About 52.7 and 48.8% of the induced micronuclei, respectively, were centromere-positive, indicating their formation by whole chromosomes and reflecting the aneugenic activity of both compounds. Correspondingly, about 47.3 and 51.2% of the induced micronuclei, respectively were centromere-negative, demonstrating that topotecan and irinotecan not only induce chromosome loss but also DNA strand breaks. Both the clastogenic and aneugenic potential of these drugs can lead to the development of secondary tumors and abnormal reproductive outcomes. Therefore, the clinical use of these agents must be weighed against the risks of secondary malignancies in cured patients and persistent genetic damage of their potential offspring.

Current role and future aspects of topotecan in relapsed ovarian cancer

BACKGROUND

Ovarian cancer is the fifth leading cause of cancer deaths in women. It is associated with a poor prognosis, as the majority of patients present with advanced disease and relapse after radical surgery, and following chemotherapy with carboplatin and paclitaxel.

OBJECTIVE

To review the role of topotecan in the treatment of advanced and relapsed ovarian cancer, and the efficacy and safety of novel dosing regimens and formulations of topotecan. It will also discuss further options of combination of topotecan with other cytotoxic agents and targeted therapies.

RESEARCH DESIGN AND METHODS

The authors searched for relevant references in the MEDLINE database and in congress abstracts of the American Society of Clinical Oncology.

RESULTS

Topotecan is an established second-line therapy for advanced and relapsed ovarian cancer; a regimen of 1.5 mg/m(2)/day 1-5 has been approved in the USA and many other western countries. Topotecan is well tolerated; associated haematological toxicity is generally manageable, reversible and non-cumulative. A number of alternative dosing regimens and formulations have been investigated in an attempt to improve the toxicity profile of topotecan without compromising anti-tumour activity. A novel oral formulation of topotecan has shown clinical promise in patients with advanced and relapsed disease. Administration of i.v. topotecan on a weekly basis produced encouraging results in several phase II trials, with less haematological toxicity and similar response rates to the day 1-5 regimen. Also, recent early studies demonstrate that topotecan is effective in combination with several other therapeutic agents in the relapsed setting.

CONCLUSION

The peer-reviewed literature reports that topotecan is an effective, well tolerated treatment option for relapsed ovarian cancer.

Key role of topoisomerase I inhibitors in the treatment of recurrent and refractory epithelial ovarian carcinoma

Ovarian cancer remains one of the most difficult gynecologic cancers to treat, owing to its aggressive biology and high relapse rate, as well as the toxic side effects of available chemotherapeutic agents used to treat recurrent disease. Topoisomerase I inhibitors, including topotecan and irinotecan, are some of the most effective and tolerable treatment options for recurrent ovarian cancer. The ideal dosing, timing of administration, role in combination with other chemotherapies or biologics and potential role in up-front therapy remains an area of active research. This article reviews the mechanism of action of topoisomerase I inhibitors and the efficacy, dosing, schedule and toxicity for topotecan, irinotecan, 9-nitrocamptothecin, DX-8951 and 9-aminocamptothecin. Conclusions include a discussion of future avenues of research and ongoing projects.

Preparation, optimization, and characterization of topotecan loaded PEGylated liposomes using factorial design

This study reports the development of liposomal system for a potent antitumor drug, topotecan. To achieve this goal conventional and PEGylated liposomes were prepared according to a factorial design by hydration method followed by extrusion. Parameters such as type of lipid, percentage of cholesterol, percentage of phosphatidylglycerols, percentage of polyethylene glycol (PEG)-lipids, and drug to lipid molar ratio were considered as important factors for the optimizing the entrapment and retention of topotecan inside the liposomes. The size and zeta-potential of the PEGylated and conventional liposomes were measured by particle size analyzer and zeta-potentiometer, respectively. The stability and release characteristics of PEGylated liposome loaded topotecan were compared with conventional liposomes and free topotecan. The optimized PEGylated [distearoyl phosphatidylcholine (DSPC)/cholesterol/ distearoyl phosphatidylglycerol (DSPG)/ distearoyl phosphatidylethanolamine-PEG(2000) (DSPE-PEG(2000)); 7:7:3:1.28] and related conventional [DSPC/cholesterol/DSPG; 7:7:3] liposomes showed a narrow size distribution with a polydipersity index of 0.15 and 0.10, an average diameter of 103.0 +/- 13.1 and 95.2 +/- 11.10 nm, and with drug loading of 11.44 and 6.21%, respectively. Zeta-potential was -10 +/- 2.3 and -22 +/- 2.8 mV for PEGylated and conventional liposomes, respectively. The results of stability evaluation showed that the lactone ring of topotecan was notably preserved upon liposome encapsulation. PEGylated liposomes containing topotecan showed a significant decrease (P < 0.001) in release rate in comparison with conventional leptosomes. These results indicate the suitability of PEGylated liposomes in controlling topotecan release. The prepared liposomes (especially PEGylated liposomes) as those described here may be clinically useful to stabilize and deliver topotecan for the treatment of cancer.

Topotecan for ovarian cancer

BACKGROUND

Chemotherapeutic agents such as topotecan can be used to treat ovarian cancer. The effects of using topotecan as a therapeutic agent have not been previously been systematically reviewed.

OBJECTIVES

To systematically evaluate the effectiveness and safety of topotecan for the treatment of ovarian cancer.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), (Issue 4, 2006); Cochrane Gynaecological Cancer Review Group (CGCRG) Specialised Register (Cochrane Library Issue 4, 2006); MEDLINE (January 1990 to 27 July 2006); EMBASE (January 1990 to 27 July 2006); The European Organization for the Research and Treatment of Cancer (EORTC) database (to 1 August 2006); CBM (Chinese Biomedical Database) (January 1990 to 27 July 2006).

SELECTION CRITERIA

Randomised controlled trials (RCTs) which randomized patients with ovarian cancer to single or combined use of topotecan versus interventions without topotecan, or different remedies of topotecan.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted and analysed data.

MAIN RESULTS

Six studies including 1323 participants were eligible for this review (Gordon 2004a; Gore 2001a; Gore 2002; Hoskins 1998; Huinink 2004; Placido 2004) All studies, as reported, were identified as being of poor methodological quality. Topotecan had comparable effectiveness to prolong progression-free survival (PFS) compared with pegylated liposomal doxorubicin (PLD), (16.1 weeks versus 17.0 weeks; p = 0.095). Overall survival (OS) time was similar in participants using PLD compared with topotecan (56.7 weeks versus 60 weeks; p = 0.341). Topotecan was more hematologically toxic compared with paclitaxel or PLD, relative risks (RRs) of hematological events: ranged from 1.03 to 14.46 and 1.73 to 27.12 respectively. A 21-day cycle of topotecan was more toxic than a 42-day cycle (RRs of hematological and non-hematological events ranged from 1.03 to 8). Intravenous and oral topotecan had comparable toxicity. Topotecan delayed progression more effectively compared with paclitaxel (23.1 weeks versus 14 weeks, p = 0.0021). Participants were more likely to respond to topotecan on a 21-day cycle as opposed to a 42-day cycle (RR 7.23, 95% CI 0.94 to 55.36). Small tumor diameter, sensitivity to platinum-based chemotherapy was associated with better prognosis. Small sample size, methodological flaws and poor reporting of the included trials made measurement bias of the trials difficult to assess.

AUTHORS' CONCLUSIONS

Topotecan appears to have a similar level of effectiveness as paclitaxel and PLD, though with different patterns of side effects. Larger, well-designed RCTs are required in order to define an optimal regime.

Natural products as leads to anticancer drugs

Throughout history, natural products have afforded a rich source of compounds that have found many applications in the fields of medicine, pharmacy and biology. Within the sphere of cancer, a number of important new commercialised drugs have been obtained from natural sources, by structural modification of natural compounds, or by the synthesis of new compounds, designed following a natural compound as model. The search for improved cytotoxic agents continues to be an important line in the discovery of modern anticancer drugs. The huge structural diversity of natural compounds and their bioactivity potential have meant that several products isolated from plants, marine flora and microorganisms can serve as "lead" compounds for improvement of their therapeutic potential by molecular modification. Additionally, semisynthesis processes of new compounds, obtained by molecular modification of the functional groups of lead compounds, are able to generate structural analogues with greater pharmacological activity and with fewer side effects. These processes, complemented with high-throughput screening protocols, combinatorial chemistry, computational chemistry and bioinformatics are able to afford compounds that are far more efficient than those currently used in clinical practice. Combinatorial biosynthesis is also applied for the modification of natural microbial products. Likewise, advances in genomics and the advent of biotechnology have improved both the discovery and production of new natural compounds.

Safety of topotecan in the treatment of recurrent small-cell lung cancer and ovarian cancer

The topoisomerase I inhibitor, topotecan, is approved for the treatment of recurrent small-cell lung cancer (SCLC) and ovarian cancer (OC). Patients with recurrent SCLC and OC typically experience multiple relapses and receive multiple rounds of chemotherapy. In these settings, disease stabilisation is considered a treatment benefit, and quality-of-life effects and cumulative toxicities of treatments should be considered. Many patients with recurrent cancer may be predisposed to treatment-related adverse events because of advanced age, renal impairment or extensive prior therapy. The standard regimen of topotecan, 1.5 mg/m(2) on days 1-5 of a 21-day cycle, has generally mild nonhaematological toxicity and a well-defined haematological toxicity profile characterised by reversible and noncumulative neutropenia. Alternative regimens may lower the incidence of haematological toxicities and maintain antitumour efficacy. Topotecan may provide physicians with a versatile therapeutic option for the treatment of patients with relapsed SCLC or OC.

A comparison of patients with relapsed and chemo-refractory gestational trophoblastic neoplasia

The majority of women requiring chemotherapy for gestational trophoblastic disease (GTN) are cured with their initial chemotherapy treatment. However, a small percentage either become refractory to treatment, or relapse after the completion of treatment. This study investigates the characteristics and outcome of these patients. Patients were identified from the Charing Cross Hospital GTD database. The outcome of these patients with relapsed disease was compared to those with refractory disease. Between 1980 and 2004, 1708 patients were treated with chemotherapy for GTN. Sixty (3.5%) patents relapsed following completion of initial therapy. The overall 5-year survival for patients with relapsed GTN was 93% (95% CI 86-100%). The overall survival for patients with low-risk and high-risk disease at presentation, who subsequently relapsed was 100% (n=35), and 84% (n=25) (95% CI: 66-96%: P<0.05), respectively. Eleven patients were identified who failed to enter remission and had refractory disease. These patients had a worse outcome compared to patients with relapsed disease (5-year survival 43% (95% CI:12-73% P<0.01)). The outcome of patients with relapsed GTN is good. However, patients with primary chemo-refractory disease do poorly and novel therapies are required for this group of patients.

Phase I clinical trial of topotecan and pegylated liposomal doxorubicin

BACKGROUND

The objective of this study was to determine the feasibility and maximum tolerated dose (MTD) of combination topotecan and pegylated liposomal doxorubicin (PLD) administered in 4- or 3-week cycles in patients with advanced or refractory solid tumors.

PATIENTS AND METHODS

Patients were treated with intravenous topotecan (0.75-1.25 mg/m2) for 3 days followed by PLD (25-40 mg/m2) on Day 4. The following dose combinations (topotecan/PLD, mg/m2) were explored: 0.75/40, 1.0/40, and 1.25/40 every 28 days; and 1.0/25 and 1.0/30 every 21 days.

RESULTS

Thirty-two patients were enrolled, and all had received prior chemotherapy. Most (84 percent) patients had ovarian cancer. A total of 157 cycles (median, 4 cycles; range, 1-19 cycles) of chemotherapy were administered. Dose-limiting toxicities were Grade 4 neutropenia and death at dose level 3 (1.25/40 mg/m2 every 28 days), and neutropenic fever, Grade 3 stomatitis, and Grade 3 peripheral neuropathy (all in one patient) at dose level 5 (1/30 mg/m2 every 21 days). Myelosuppression was the most common serious toxicity. Twenty-six patients were evaluable for response and 7 (27 percent) had partial responses. All responses were seen in patients with ovarian cancer.

CONCLUSIONS

This combination is feasible and well tolerated; encouraging activity was observed in heavily pretreated patients with ovarian cancer. The recommended regimens for a Phase II study are topotecan 1.0 mg/m2 on Days 1-3 followed by PLD 40 mg/m2 on Day 4 of a 28-day cycle, and topotecan 1.0 mg/m2 on Days 1-3 and PLD 30 mg/m2 on Day 4 of a 21-day cycle.

Plant-based anticancer molecules: a chemical and biological profile of some important leads

A number of natural products, with diverse chemical structures, have been isolated as anticancer agents. Several potential lead molecules such as camptothecin, vincristine, vinblastine, taxol, podophyllotoxin, combretastatins, etc. have been isolated from plants and many of them have been modified to yield better analogues for activity, toxicity or solubility. Several successful molecules like topotecan, irinotecan, taxotere, etoposide, teniposide, etc. also have emerged as drugs upon modification of these natural leads and many more are yet to come. In this review, the authors have focused on four important anticancer leads, that is, camptothecin, taxol, combretastatin A-4 and podophyllotoxin. Their chemistry, structure and activity relationships, biological activities, modes of action, analogue synthesis and future prospects have been discussed.

Topotecan in heavily pretreated patients with recurrent ovarian, peritoneal, and fallopian tube carcinoma

Topotecan has demonstrated antitumor activity in heavily pretreated patients with ovarian carcinoma. This report examines the activity and toxicity of topotecan in 29 heavily pretreated patients with recurrent ovarian, peritoneal, and fallopian tube carcinoma. Topotecan 1.5 mg/m2 was administered intravenously on days 1-5, every 21 days. It was second-line chemotherapy in 6 (20.7%) patients, third-line in 15 (51.7%), fourth-line in 4 (13.8%), fifth-line in 3 (10.3%), and seventh-line in 1 (3.4%). Median dose intensity was 1.667 mg/m(2)/week, and median relative dose intensity was 0.67. Disease complete response was observed in 5 (17.2%) patients, partial response in 1 (3.4%), stable disease in 12 (41.4%), and progressive disease in 11 (37.9%). CA-125 complete response was observed in 3 (10.3%) patients, partial response in 11 (37.9%), stable level in 5 (17.2%), and progressive level in 9 (31%), and no data were available in 1 (3.4%) patient. Toxicity was mainly hematologic: grade 3-4 neutropenia was observed in 20 (69%) patients, grade 3-4 leukopenia in 12 (41.4%), grade 3-4 thrombocytopenia in 9 (31%), and grade 3-4 anemia in 2 (6.9%). It is concluded that topotecan has considerable activity and noncumulative hematologic toxicity in heavily pretreated patients with recurrent ovarian, peritoneal, and fallopian tube carcinoma.

Cell cycle effects of topotecan alone and in combination with irradiation

BACKGROUND AND PURPOSE

To elucidate the role of TP53 on differential effects of topoisomerase I inhibitor topotecan (Hycamtin on radiation sensitivity.

MATERIALS AND METHODS

Cell cycle distribution and protein expression of TP53, p21(WAF1/CIP1) and cyclin B was studied in CCD32 lung fibroblasts, glioblastoma cell lines U118 (mutant TP53), and U87 (wildtype TP53) after treatment with topotecan (0.05 and 1 microM) and/or ionizing radiation (2 Gy).

RESULTS

Cell cycle effects varied with topotecan concentration, resulting in G1 arrest (1 microM), or S/G2/M arrest (0.05 microM), and was modified differentially in fibroblasts and in glioblastoma cells in combination with irradiation. Phosphorylation of TP53 and expression of p21(WAF1/CIP1) was induced by IR and/or topotecan in CCD32 cells, and in U118 cells after topotecan treatment, accompanied by cyclin B degradation. In U87 cells only 1 microM topotecan generated phosphorylation of TP53 and p21(WAF1/CIP1) expression; 0.05 microM caused stabilization of cyclin B.

CONCLUSIONS

The antagonistic effect of combined topotecan/irradiation treatment in fibroblasts was most likely due to an immediate radiation induced G1 arrest, but was not observed in p53 wildtype glioblastoma cells. Thus, the impact of TP53 on the topotecan response remains indistinct, and is obviously influenced by other genomic alterations acquired by tumor cells.

p53 Gene Status and Response to Topotecan-Containing Chemotherapy in Advanced Ovarian Carcinoma

OBJECTIVE

Since the p53 gene has been identified as a determinant of response to chemotherapy in ovarian carcinoma in previous studies, we investigated the significance of the p53 status in response to topotecan as second-line therapy.

METHODS

Twenty-eight patients with advanced ovarian carcinoma, pretreated with standard platinum/paclitaxel chemotherapy, received topotecan as single-agent second-line therapy. Tumors were investigated by molecular analysis for p53 mutations in tumor samples obtained at primary surgery (i.e. before first-line therapy).

RESULTS

Wild-type p53 tumors responsive to first-line therapy maintained substantial responsiveness to topotecan. In contrast, p53 mutation was associated with a low responsiveness to second-line therapy.

CONCLUSIONS

The better outcome in relapsed patients with wild-type p53 suggests that the presence of a functional wild-type p53 confers stability of the drug-sensitive phenotype. This outcome is consistent with the clinical observation that the efficacy of topotecan in the treatment of relapsed ovarian carcinoma patients is dependent on platinum sensitivity, because platinum-sensitive tumors are expected to carry wild-type p53. Although untreated mutant p53 tumors may be responsive to first-line paclitaxel-containing therapy, it is likely that loss of p53 leads to genomic instability resulting in rapid progression to drug resistance.

Weekly topotecan in heavily pretreated patients with recurrent epithelial ovarian carcinoma

OBJECTIVE

To investigate weekly topotecan in heavily pretreated patients with recurrent ovarian cancer.

METHODS

The records of patients with recurrent epithelial ovarian cancer who were treated with weekly topotecan after failure of > or =1 prior regimen were reviewed. Patients received topotecan (median starting dose approximately 2.5 mg/m(2)) on days 1, 8, and 15 of a 28-day cycle. Antitumor response was assessed after 2 cycles by serial CA-125 levels.

RESULTS

Thirty-five heavily pretreated patients received a mean of 5 cycles of topotecan (range, 1-13 cycles). Thirty-two patients had definable platinum sensitivity (16 sensitive, 8 resistant, 8 refractory). Median age was 56 years. A total of 177 cycles (534 weeks) of topotecan was administered. Hematologic toxicity was generally mild, and no grade 4 toxicities were observed. Grade 3 hematologic toxicity, including leukopenia, neutropenia, thrombocytopenia, and anemia, was observed in 2, 2, 1, and 0 patients, respectively. No patients experienced grade 3 or 4 nonhematologic toxicity. Based on serial CA-125 measurements, there were 1 (3%) complete and 5 (15%) partial responses, with 1 of the partial responses in a patient with platinum-refractory disease. Stable disease was reported in 13 (38%) patients, including 5 patients with platinum-resistant/refractory disease.

CONCLUSION

Weekly topotecan demonstrates activity and is well tolerated compared with historical data with the standard 5-day schedule. Higher doses may be warranted because of the high tolerability shown for weekly topotecan. Weekly topotecan may be an appropriate treatment option for patients with recurrent ovarian cancer, especially heavily pretreated patients who might require dosing schedules with improved tolerability.

Distinction between serous tumors of low malignant potential and serous carcinomas based on global mRNA expression profiling

OBJECTIVES

The molecular pathogenesis of ovarian serous tumors of low malignant potential (S-LMP) is not well understood, although the collective data suggest that they arise through molecular mechanisms distinct from those leading to conventional serous carcinomas (S-Ca). To further examine the molecular differences between these two diseases, we studied the gene expression pattern of ovarian S-LMP and S-Ca using high-density spotted cDNA and tissue microarrays.

METHODS

Total RNA from 23 ovarian S-LMP and S-Ca was analyzed on 43,200 spot cDNA microarrays and the differential expression of proteins encoded by differentially expressed genes was validated using tissue microarrays.

RESULTS

Unsupervised hierarchical clustering analysis of filtered data showed a complete separation between S-LMP and S-Ca, based predominantly on a small set of genes expressed at higher levels in S-LMP than in S-Ca. Many genes previously identified as up-regulated in ovarian carcinoma relative to normal ovarian tissue were expressed at even higher levels in S-LMP. These genes included mucin-1, mesothelin, HE4, PAX 8, and apolipoprotein J/clusterin. Immunohistochemical staining of tissue microarrays confirmed higher expression of selected proteins encoded by these genes in the S-LMP. Few genes were expressed at a higher level in S-Ca; these included E2F1, topoisomerase IIalpha, and cyclin E, with higher levels of cyclin E protein confirmed by immunohistochemistry.

CONCLUSIONS

S-LMP and S-Ca are distinguished at the molecular level by a relatively small gene set, suggesting the pathogenesis of S-LMP as well as S-Ca may involve molecular pathways that escape detection by global gene expression profiling. In order to obtain biologically and clinically relevant information about the mechanisms involved in ovarian carcinogenesis, future studies based on molecular profiles of ovarian cancer should include analyses of low malignant potential tumors. Inclusion of such tumors is also critical to the evaluation of the efficacy of potential new diagnostic and/or therapeutic biomarkers.

Retrospective analysis of weekly topotecan as salvage therapy in relapsed ovarian cancer

OBJECTIVE

To retrospectively investigate the safety and efficacy of weekly topotecan in heavily pretreated patients with ovarian cancer.

METHODS

Data were collected by retrospective review of patient records. Eligible patients had received > or =2 prior regimens for ovarian cancer before treatment with weekly topotecan. Efficacy was determined by measurable disease or CA 125 levels. Adverse event and growth factor support data were also collected.

RESULTS

Fifty patients (median age, 61 years) were evaluable for safety and received a total of 244 4-week cycles of therapy (median, 3; range, 1-21 cycles). Most patients (84%) had measurable disease, and 30% had performance status of > or =2. Patients had received two to six prior treatments for ovarian cancer. Median weekly dose per patient was topotecan 3.7 mg/m(2). Grade 4 hematologic toxicities (generally manageable) occurred in 4% of patients. One patient had febrile neutropenia. Grade 3/4 nonhematologic toxicities were fatigue in two (4%) patients. Forty-two patients were evaluable for response. Of 35 evaluable patients with measurable disease, 11 (31%) had a partial response (median duration, 3 months), and 15 (43%) patients had stable disease (median duration, 3.5 months). Of 41 evaluable patients with elevated CA 125 (median, 154 U/l; range, 47-7200 U/l), 11 (27%) had > or =50% decreases or normalization of CA 125 levels. Median time to progression in all patients with stable disease has not been reached (follow-up range, 1.5-17.3 months).

CONCLUSIONS

Weekly topotecan is active and well tolerated in heavily pretreated patients with relapsed ovarian cancer. Prospective studies of this regimen are warranted.

Combined Directed Ortho Metalation/Cross-Coupling Strategies: Synthesis of the Tetracyclic A/B/C/D Ring Core of the Antitumor Agent Camptothecin

A convergent synthesis of the A/B/C/D ring fragment 5 of camptothecin using a combination of directed ortho metalation and Negishi cross-coupling is described. The key features of the synthetic sequence are an anionic ortho-Fries rearrangement (10 --> 12), a Negishi cross-coupling (7 --> 6), and a terminal modified von Braun reaction (16 --> 5) that leads to tetracyclic derivative 5 in 7 steps and 11% overall yield.

An evaluation of transmembrane ion gradient-mediated encapsulation of topotecan within liposomes

Topotecan can be encapsulated in liposomes, however little is known about the role encapsulated counter ions play in drug loading efficiency and drug release. Using 1,2-distearoyl-sn-glycero-3 phosphatidylcholine and cholesterol liposomes (55:45 mole ratio), encapsulation was achieved using manganese ion gradients (MnSO(4) or MnCl(2)), with the addition of A23187, a divalent cation/proton exchanger, to maintain a pH gradient. This methodology was compared to procedures where the pH gradient was generated by use of encapsulated (NH(4))(2)SO(4) or citrate (300 mM, pH 3.5). All methods facilitated topotecan encapsulation. Liposomes prepared in the presence of the citrate and MnCl(2) (+A23187) exhibited reduced loading capacities. Liposomes prepared in the presence of (NH(4))(2)SO(4) and MnSO(4) (+A23187) could be used to generate liposomes exhibiting a drug-to-lipid ratio of 0.3 (wt/wt) with an encapsulation efficiency of >90%. In vitro drug release data suggested that the (NH(4))(2)SO(4) and MnSO(4) (+A23187) formulations released drug at a reduced rate. For these formulations, the drug release rates decreased as the drug-to-lipid ratio (wt/wt) increased from 0.1 to 0.2. Cryo-electron micrographs indicated that encapsulated topotecan precipitated as linear particles within liposomes. The stability of topotecan loaded liposomes appeared to be dependent on the presence of both a pH gradient and encapsulated sulfate.

A phase II study to determine the efficacy and tolerability of intravenous ZD9331 in heavily pretreated patients with ovarian cancer

OBJECTIVES

This Phase II, multicenter, open-label study was conducted to assess the efficacy and tolerability of ZD9331, a novel direct-acting thymidylate synthase inhibitor, in heavily pretreated patients with ovarian cancer.

METHODS

The study recruited 44 women with ovarian cancer or primary peritoneal cancer previously treated with platinum therapy and paclitaxel and with progressive disease after, or intolerance to, topotecan administered as the most recent therapy. ZD9331 was administered as an intravenous infusion at 130 mg/m(2) on Days 1 and 8 of 3-week cycles, until objective evidence of disease progression. A cutoff date of 3 months after the last patient received the first dose was set for data collection.

RESULTS

Patients received a mean of 3.3 cycles of ZD9331 and a total of 143 cycles were administered. Among the 42 patients evaluated for best overall tumor response, one achieved a complete response and two achieved a partial response, giving an objective tumor response rate of 7%. The complete response occurred at Day 15 of Cycle 2 in a patient receiving ZD9331 as her eighth-line therapy. Seven patients had stable disease, giving a disease control rate of 23%. Thirty-one patients (71%) had disease progression and the median time to progression was 53 days. Most patients (89%) experienced drug-related adverse events, most commonly nausea (73%), vomiting (48%), and neutropenia (50%). Six patients (14%) were withdrawn from treatment due to adverse events.

CONCLUSIONS

The preliminary evidence of efficacy and acceptable tolerability of ZD9331 in this heavily pretreated population with ovarian cancer warrants further investigation, especially in a less heavily pretreated patient population.

First-line treatment regimens and the role of consolidation therapy in advanced ovarian cancer

Current first-line management for advanced ovarian cancer consists of cytoreductive surgery followed by chemotherapy, usually with a platinum/taxane combination. Although this approach has been shown to achieve overall response rates of 70-80% in clinical trials, the majority of patients relapse. A number of different approaches have been investigated to improve the efficacy of therapy, including the introduction of newer agents, such as topotecan, into chemotherapy regimens and the use of consolidation therapy. Encouraging results have been obtained in clinical trials of topotecan administered using a variety of different approaches, including replacement regimens, triplet regimens, and sequential doublet regimens. Other treatment modalities have included the use of drug resistance modifiers and intraperitoneal delivery of treatment. A variety of approaches to consolidation therapy have also been investigated, including radiotherapy, cytotoxic therapy, and intraperitoneal therapy. The use of topotecan has also shown promise in this setting, although further data from large, controlled trials are required. In summary, while good response rates are obtained using current first-line treatments, the high relapse rate indicates the need to develop more effective and durable treatment regimens including new agents with, perhaps, an increased emphasis on maintaining remission through the use of consolidation therapy.

Emerging role of topotecan in front-line treatment of carcinoma of the ovary

The conventional front-line chemotherapy strategy for advanced epithelial ovarian carcinoma has become adjuvant administration of platinum (carboplatin and cisplatin), either alone or, most often, in combination with a taxane. However, a number of active agents have been identified in phase II/III trials of second-line and salvage ovarian cancer patients that may augment this front-line strategy. One agent, topotecan, has antitumor activity comparable with paclitaxel in patients with recurrent ovarian cancer and is an established treatment in second-line or salvage settings. Additionally, its mechanism of action is different from paclitaxel and is nonoverlapping. These properties, coupled with the in vitro synergy observed in tumor models among topotecan, paclitaxel, and platinum, have provided the rationale for investigators to examine topotecan in front-line ovarian cancer therapy. A number of strategies for incorporating topotecan into front-line therapy are under active investigation, including the replacement of paclitaxel with topotecan, a triplet regimen with cisplatin or carboplatin and paclitaxel, a consolidation regimen consisting of several courses of a platinum agent and paclitaxel followed by several courses of topotecan, and a sequential doublet regimen in which patients receive platinum in every course as part of a doublet with alternating or sequential topotecan and paclitaxel. Preliminary data from ongoing clinical trials of these new regimens show favorable response rates and generally manageable toxicity profiles. This review summarizes the preliminary clinical findings associated with the four strategies and outlines ongoing and future randomized studies of topotecan in front-line ovarian cancer.

Update on the treatment of cervical and uterine carcinoma: focus on topotecan

Carcinomas of the uterine cervix and corpus are significant causes of morbidity and mortality among women in the U.S. and are expected to contribute 10,700 deaths in 2002. Despite the widespread use of cytologic screening and improvements in early diagnosis, mortality rates have changed little over the past 25 years, and the management of cervical and uterine cancers remains a significant unmet medical need. Currently available modalities, including radiotherapy and cisplatin-based chemotherapy, provide suboptimal control of disease, and there are no effective treatments for recurrent disease. The antitumor activity and tolerability of a number of novel agents, including topoisomerase I inhibitors, vinca alkaloids, taxanes, and gemcitabine, have been of considerable interest in treatment of these cancers. This review discusses current trends in the treatment of cervical and endometrial carcinomas, focusing on the potential role of topotecan in the treatment of non-ovarian gynecologic malignancies.

Management of treatment-related toxicity in advanced ovarian cancer

Recognition of recurrent ovarian cancer as a disease with significant secondary responses and remissions has led to an increase in the need for oncologists to plan for the long-term therapy of patients. However, many of the currently available front-line and salvage agents used in advanced ovarian cancer are associated with cumulative and/or irreversible toxicities that pose challenges in long-term planning. The irreversible effects associated with some of these therapies may render patients less tolerant to subsequent treatments and lead to a cycle of diminishing treatment options with each remission and disease relapse. Additionally, the potential for patients to experience cumulative toxicity must be carefully weighed against the goals of prolonging the disease-free interval and improving patient quality of life. A number of agents are available in the treatment armamentarium (platinum, paclitaxel, gemcitabine, etoposide, liposomal doxorubicin, and topotecan), many, but not all of which are associated with cumulative toxicity. For instance, cumulative neurotoxicity associated with cisplatin as first-line therapy may diminish the option for retreatment with platinum at first relapse. In contrast, the main toxicity associated with topotecan is noncumulative, manageable myelosuppression. In this review, the major toxicities associated with the predominant chemotherapy agents used in advanced ovarian cancer are discussed along with selected management approaches in the context of long-term treatment planning and sequencing.

Alternate dosing schedules for topotecan in the treatment of recurrent ovarian cancer

Topotecan has demonstrated efficacy in the treatment of both platinum-sensitive and platinum-resistant recurrent ovarian cancer. However, the optimal dosing for topotecan has not been established. The standard dosing regimen is 1.5 mg/m(2)/day on days 1-5 of a 21-day cycle, with response rates ranging from 13%-33%. Although the resulting hematologic toxicities are reversible and noncumulative, this schedule is associated with significant myelosuppression. Ongoing clinical phase I and II trials have evaluated alternative dosing schedules such as the 21-day 24-hour continuous intravenous (c.i.v.), the 3-day i.v. bolus, the weekly 72-hour c.i.v., the weekly 24-hour c.i.v., and the weekly bolus i.v. regimens. Prolonged exposure to topotecan has been shown to increase the efficacy of topotecan, whereas shorter regimens decrease exposure to the drug and therefore decrease toxicity. Preliminary studies investigating the weekly bolus i.v. regimen have demonstrated response rates comparable with those achieved with the standard dosing regimen, with a lower frequency of severe toxicity. Although randomized, controlled comparative trials are necessary to determine relative efficacy, results from studies utilizing other alternative regimens are less encouraging, especially for lower-risk patients with platinum-sensitive ovarian cancer who are likely to tolerate higher doses of topotecan. Optimizing the dosing regimen will also increase the quality of life for the patient through increased efficacy, decreased toxicity, and increased convenience of administration. Continued investigation of the weekly i.v. bolus is needed to fully elucidate the contribution of this regimen to the current armamentarium used in the treatment of patients with relapsed ovarian cancer.

Relapsed ovarian cancer: challenges and management strategies for a chronic disease

Advances in the treatment and early detection of ovarian cancer have led to gains in 5-year survival rates, with 52% of women diagnosed between 1992 and 1997 surviving 5 years or longer, compared with 41% of women diagnosed between 1983 and 1985. Although approximately 10%-15% of patients achieve and maintain complete responses to therapy, the remaining patients have persistent disease or eventually relapse. These patients will generally undergo a series of treatments, each associated with progressively shorter treatment-free intervals. Nevertheless, median survival of patients with recurrent ovarian cancer ranges from 12-24 months, demonstrating the chronic natural history of the disease. Advances in the treatment of ovarian cancer over the past decade have led to these improvements and have prompted oncologists to now view the management of patients with ovarian cancer as an ongoing, long-term challenge. This shift in approach has raised important new questions regarding patient management, including the need to define trigger points for initiating or changing treatment (e.g., sequential increases in serum cancer antigen 125 levels, appearance of symptoms, or cumulative toxicities), anticipation of impending treatment decision points, recognition that the overtreatment of patients early in the disease process may adversely affect future treatment opportunities, and a renewed emphasis on patient education and participation in decision-making. This review will discuss these important patient management issues and will conclude with case studies illustrating two distinct treatment strategies (planning and sequencing) for the long-term management of patients with ovarian cancer.